1) Field of the Invention
The present invention relates to a converter capable of making a five-wire or six-wire resistive touch screen compatible with a four-wire controller, more particularly, to a five-wire or six-wire touch screen connected with a converting circuit to be compatible with a four-wire controller.
2) Description of the Prior Art
Accordingly, regular touch screens available on the market are divided into a four-wire resistive touch screen and a five-wire or six-wire resistive touch screen. A typical structure of a four-wire resistive touch screen, as indicated in FIGS. 4 and 5, comprises a parallel-serial resistor loop formed by two electrode wires on two different planes of an upper sheet electrode plate and a lower sheet electrode plate. The main structure thereof has a lower base plate made of glass (A) printed with a lower conductive film (A1) or ITO sheet, a set of isolating point sheet (G), an isolating sheet (B), a silver conductive sheet (D, D2), a linear sheet (C), another isolating sheet (F), an upper conductive film (E1) or ITO sheet and a plastic film (E); wherein one connecting end of a bus line (T) connects with a connecting end (D1) of the silver conductive sheet (D). Another connecting end of the bus line (T) connects with a four-wire controller (not shown). According to the working principle, the four-wire controller conducts the silver conductive sheets (D, D2) to form a parallel-serial resistor loop inbetween; wherein the lower conductive film (A1) forms an evenness filed in an X-axis direction. When the plastic film (E) is touched, the upper conductive sheet (E1) contacts the lower conductive film (A1) via the isolating point (G) thereby detecting the reference voltage of the contact point. The voltage level ratio stands for the ratio of the directional position (or X-axis direction) on the touch screen. After detecting the direction, the four-wire controller converts the upper conductive film (E1) to an evenness field in a Y-axis direction. The lower conductive film (A1) detects the voltage level of the upper touch point for further detecting the position of another Y-axis direction. For detail working principle, please refer to U.S. Pat. No. 3,622,105.
Referring to FIG. 5, the upper silver sheet (D2) and the lower silver sheet (D) are not on the same plane; they are connected by a silver glue point (D4) to form a parallel-serial resistor loop; when the upper plastic film (E) is touched, the field between the upper and the lower silver sheets (D, D2) starts to change thereby generating voltage signals at four different coordinates for output.
The five-wire resistive touch screen has only one electropolar sheet on the same plane. As indicated in FIG. 6, a silver sheet (E) or the electropolar wire is printed on an isolating sheet (B) as a single electropolar sheet. As indicated in FIG. 7, the difference between the six-wire and a five-wire touch screens is that the bottom of glass (A) is printed with a sheet of conductor wire (B) with a ground connecting end (B1) for eliminating the noise. The six-wire touch screen also has only one electropolar sheet or silver sheet (E). However, the main difference between the four-wire resistive touch screen and the five-wire or six-wire touch screen is that, when being touched, the four-wire resistive touch screen generates four voltage signals X+, Y+, Yxe2x88x92, Xxe2x88x92, but the five-wire or six-wire touch screen generates five voltage signals (X+, Y+), (X+, Yxe2x88x92), (Xxe2x88x92, Y+), (Xxe2x88x92, Yxe2x88x92) and (Y+, X+). The four-wire controller processes the four voltage signals generated by the four-wire touch screen. The five-wire controller processes the five voltage signals generated by the five-wire or six-wire touch screen. Obviously, the advanced five-wire or six-wire touch screen is not compatible with the traditional four-wire controller available in many computer systems. For using the five-wire controller for the advanced five-wire or six-wire touch screen, the old four-wire controller (including the entire computer system) has to be replaced and that is considered a waste in terms of cost.
Therefore, how to utilize a converter device or circuit to connect with the traditional four-wire controller to make it compatible with the five-wire or six-wire resistive touch screen is the research issue of the present invention.
Therefore, the primary objective of the present invention is to provide a converter capable of making a resistive (voltage type) five-wire or six-wire touch screen to be compatible with a four-wire controller; a connecting end of the four-wire controller in a computer system connects with a converter or circuit to connect with a connecting end of a five-wire or six-wire touch screen to recompose, encode and decode the voltage signals (I/O signals) output or input by the five-wire or six-wire touch screen so as to make the processed voltage signals compatible with the four-wire controller for processing.
To enable a further understanding of the structural features and the technical contents of the present invention, the brief description of the drawings below is followed by the detailed description of the preferred embodiment.